/*
 * Copyright (c) 2013, SRI International
 * All rights reserved.
 * Licensed under the The BSD 3-Clause License;
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 * 
 * http://opensource.org/licenses/BSD-3-Clause
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of the aic-expresso nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.sri.ai.brewer.parsingexpression.helper;

import java.util.Collection;
import java.util.Stack;

import com.google.common.annotations.Beta;
import com.sri.ai.brewer.api.ParsingExpression;
import com.sri.ai.brewer.api.ParsingProcess;
import com.sri.ai.brewer.core.DefaultParsingResult;
import com.sri.ai.brewer.core.ParsingResult;
import com.sri.ai.brewer.parsingexpression.core.AbstractParsingExpression;
import com.sri.ai.brewer.parsingexpression.core.Kleene;
import com.sri.ai.brewer.parsingexpression.core.Sequence;
import com.sri.ai.brewer.parsingexpression.core.Terminal;
import com.sri.ai.expresso.api.SyntaxTree;
import com.sri.ai.expresso.core.DefaultCompoundSyntaxTree;
import com.sri.ai.util.Util;

/**
 * A parsing expression for function applications.
 * 
 * @author braz
 */
@Beta
public class ParsingExpressionForFunctionApplications extends AbstractParsingExpression {
	private static final long serialVersionUID = 1L;

	public ParsingExpressionForFunctionApplications(ParsingExpression functorParsingExpression, ParsingExpression eachArgumentParsingExpression) {
		super("function application", functorParsingExpression, eachArgumentParsingExpression);
	}

	public ParsingExpressionForFunctionApplications(ParsingExpression functorAndEachArgumentParsingExpression) {
		this(functorAndEachArgumentParsingExpression, functorAndEachArgumentParsingExpression);
	}

	private final Sequence intermediate = new Sequence(get(0), new Terminal("("), new Kleene(get(1), new Terminal(",")), new Terminal(")"));

	@Override
	protected ParsingResult parsingResultAfterBookkeeping(ParsingProcess process) {
		ParsingExpression equivalent = intermediate;
		ParsingResult equivalentParsingResult = equivalent.parsingResult(process);
		
		if (DefaultParsingResult.isSuccessful(equivalentParsingResult)) {
			SyntaxTree arguments = equivalentParsingResult.getParse().getSubTree(1); // result is an application of ". (.)" to the actual functor and the argument list, so arguments are get(1)
			Object[] argumentsArray;
			if (arguments != null && arguments.hasFunctor("kleene list")) {
				argumentsArray = arguments.getImmediateSubTrees().toArray();
			}
			else {
				argumentsArray = new Object[]{arguments};
			}
			DefaultParsingResult result = new DefaultParsingResult(
					this,
					equivalentParsingResult.getTokens(),
					new DefaultCompoundSyntaxTree(equivalentParsingResult.getParse().getSubTree(0), argumentsArray), equivalentParsingResult.tokenPositionLimitInfluencedResult());
			return result;
		}
		
		return DefaultParsingResult.makeFailedParsingResult(equivalentParsingResult.tokenPositionLimitInfluencedResult());
	}

	@Override
	public Collection<ParsingExpression> parsingExpressionsToBeRegistered(ParsingProcess process) {
		Collection<ParsingExpression> result =
			Util.set(
					this,
					intermediate,
					equivalentSimplerParsingExpression(process));
		return result;
	}

	@Override
	public int computeLengthLowerBoundAfterBookkeeping(Stack<ParsingExpression> beingComputed, ParsingProcess process) {
		return intermediate.computeLengthLowerBound(beingComputed, process);
	}
}
